Pin tumbler lock



July 25, 1961 E. VAN LAHR PIN TUMBLER LOCK Filed Aug. 10, 1959 1 l a r-INVENTOR. (ea 5. Van Zak! Ohio Parkit-Lockit 60., 3609 *Church St.,Cincinnati 44, Ohio) Filed Aug. 10, 1959, 'Ser. No. 832,571 3 Claims.(Cl. 70-363) The present invention relates to an improved pin tumblerlock and has for its principal object the provision of a novel,severable connecting means between a lock of the indicated type and itsoperating key which establishes and controls the rotatable home positionof said key on the pin tumbler lock.

Another object of the invention is to provide a rugged freeze proof,tamper proof and dust proof pin tumbler lock that can readily bedisassembled and which is particularly adapted for use with coinoperated equipment where security is important, reliable performance anecessity and the flexibility of changing lock and key permutations adesirability.

A further object of the invention is to provide a lock and key severableconnecting means comprising an exterior, key engaging slot located onthe exposed surface of the lock case, rather than in the case and/or therear of the case, which will secure the production of a look having thenext preceding characteristics.

A still further object of this invention is to provide a lockconstruction that may be built on a reduced scale and of a comparativelysmaller size than locks now in use whilst increasing the ruggedness ofthe lock and the facility of changing the lock and key permutations.

Other objects of the invention will be apparent from the followingdescription taken in conjunction with the accompanying drawing showing apreferred embodiment of my invention, and wherein:

FIG. 1 is a longitudinal sectional view taken through a lock and a keyillustrative of my invention, and showing the key bit about to beassociated with the lock.

FIG. 2 is a plan view of the key bit shown in FIG. 1.

FIG. 3 is a plan view of the lock illustrated in FIG. 1.

FIG. 4 is a fragmental, side elevational view of the lock shown in FIGS.1 and 3.

FIG. 5 is a view similar to FIG. 3, showing a modification of the lock,a part being broken away and shown in section.

The lock illustrated in the drawings is operable by an adjustable key 11and is of the type in which the tumblers are movable parallel to theaxis of the tumbler plug. With reference to FIGS. 1, 3 and 4 it will benoted that the lock has a hollow, cylindrical case 12 provided at itsforward, open end with a circular, radially projecting flange 13 and anannular key engaging portion 14 extending forwardly from the flange 13.The 'lock case has a large bore 15 formed concentrically in its forwardportion and a communicating smaller bore 16 formed through its rearportion which provide an annular forwardly facing, planar shoulder 17intermediate the lock case ends which is positioned normal to thelongitudinal axis of the case and which serves to determine the shearplane of the pin tumblers. As best shown in FIG. 4 the rear exteriorportion of the lock case may have threads 18 formed therein that may beinterrupted by opposed flats 19 and which co-operate with the flange 13and a nut 200, or other device, to mount the lock case on a closure 20,or other suitable member.

A two-diameter plug 21 is journaled for rotation in the hollow case 12and comprises a large, cylindrical forward portion 22 rotatable withinthe forward bore 16 in the case and having a small cylindrical rearportion 23 rotatable in the small bore 16, the latter portion PatentedJuly 25, 1961 23 on the plug having an externally threaded shank 24integral therewith and extending rearwardly therefrom beyond the case.As is indicated in FIGS. 1 and 4 the shank is provided with a pair ofopposed flats 25 that engage an irregular hole in a latch dog 26, saiddog being mounted a desired distance behind the case by a suitablesleeve 27 and being held thereagainst by a nut 28 threaded on the shank24. It will, therefore, be noted with reference to FIG. 1 that theforward face of the large, cylindrical portion 22 of the plug 21 isflush with the forward circular face of the shoulder 14 and that therelatively wide shoulder 17 within the case provides a strong back upmeans for preventing driving of the plug through the case by blowsdirected against the plug from the outside by a person desiring to breakthe lock. A washer 29 is held against the rear face of the casing by asnap-on, spring fastener 30 snapped into a slot 31 between the shank 25and the small cylindrical portion 23 of the plug, said washer and springfastener precluding axial removal of the plug through the forward end ofthe casing.

A circular row of angularly spaced apart through holes 32 are formed inthe case, said holes having their respective axes parallel to the axisof the plug and extending through the case body between the shoulder 17and the rear face of the case. A corresponding row of angularly spacedapart holes 33 is formed through the body of the large cylindricalportion 22 of the plug 21 and are each provided with a reduced mouthportion 34 which is interposed between the forward end of the bore 33and the forward face of the plug.

The rows of holes 32 and 33 in the case 12 and the plug portion 22,respectively, are normally in aligned, locked positions and each of thealigned holes receive axially movable pairs 35 (FIG. 1) of pin tumblers,the outer tumbler of each pair having a reduced end 36 that snugly seatsin the reduced mouth portion 34 in the plug. Each pair of pin tumblersis urged forwardly by an expansile spring 37 held in the hole 32 in thecase and bearing at its forward end against the pair of tumblers, saidspring being held in compression in the hole by the washer 29. It will,therefore, be seen that in normal locked position the forward reducedend 36 of each pair of pin tumblers will seat snugly in the mouth 34 inthe plug 21 and have its outer end approximately flush with the forwardface of the plug thereby precluding the entrance of ice, rain or dustinto the interior of the case. It will also be appreciated that iceformation on this forward face may be readily scraped or chipped off bya suitable tool when required without injury to the lock parts.

The case is provided with one co-operable part of a severablekey-to-lock connecting means, said one part consisting of a plurality ofbayonet slots 38 formed in the cylindrical surface of the forwardportion 14 of the case. As best shown in FIGS. 3 and 4 each slot has anentrance portion 39 which is parallel to the common axis of the case andthe plug and a circular portion 40 concentric with said common axis,said slot communieating with the inner end of the entrance portion atright angles thereto and terminating a fixed circular distance from thesaid entrance portion.

The key 11 for my lock is shown in FIGS. 1 and 2 and includes a bitmember '41 having a circular flat base 42 that has a continuous skirt 43projecting downwardly from the periphery thereof and at right anglesthereto. The skirt has an inside diameter that is slightly larger thanthe outside diameter of the forward cylindrical part 14 of the case andis adapted to surround the said case portion when the key is axiallymoved to its home position on the lock. A circular row 44 of tumbleractuating pins of different lengths project from the base 42, the pins44 corresponding in number and position to the pairs of tumblers in theplug 21. As best shown in FIG. 1 each pin has an enlarged boss 45 andprojects through a hole 46 formed in the base '42 of the key bitportion. A means for removably securing the pins 44 in the bit portioncomprises a circular head 47 and a peripheral downturned skirt 48 formedon the head and projecting therefrom a distance equal to the thicknessof the boss 45. An irregularly shaped, integral lug 49 is formedcentrally in the head =47 and fits into an irregular hole 541 in thebase 42, the head and the base being secured together by a screw 51countersunk in the base 42 and threaded in the head 47. The key ismanipulated by a finger portion 52 integrally joined to the central partof the head 47.

The complementary part of the severable, key-to-lock connectioncomprises a series of angularly spaced apart lugs 53 projecting radiallyinwardly from the inside face of the skirt 43 on the bit portion 41 ofthe key, said lugs corresponding in number and positions to the entranceportions 39 of the bayonet slots 38 in the forward cylindrical part ofthe case.

In operation it will be understood that the key is moved axially fromits position with respect to the lock, shown in FIG. 1, to a homeposition wherein the skirt 4-3 of the key bit member 41 surrounds thecylindrical portion 14 of the lock case. In moving to this home positionthe several lugs 53 on the bit member '41 of the key move through theentrance portions 39 of the bayonet slots 38 in the case whilst the pins44 enter their respective holes 34 in the plug 21 and depress theirrespective tumbler pairs 35 until the abutting surfaces of the pairs liein the shear plane of the shoulder 17. The plug may now be rotated bythe key in the case, the amount of rotation being limited by the radialportions 40 of the slots in which the lugs move during said limitedrelative rotation.

Now referring to FIG. of the drawings which illustrate a modification ofmy lock it will be seen that a continuous, annular slot 54 is formed inthe exposed key engaging portion 14 of the lock case 12 and that twoentrance slots 55 are formed in said portion 14 which communicate withopposite portions of the slot 54. The key for this modified lock isidentical to the key shown in FIGS. 1 and 2 of the drawing except thatit has two oppositely positioned lugs in the skirt interior instead ofthe three lugs 53, as shown. This continuous, annular slot 54 isutilized where a screw type lock is desirable and it is furthercontemplated that this type of slot could be ideally employed in lookswhich have built in stop means limiting rotation of the plug in the caseor where the plug and case have cooperablestop means on the rearportions thereof.

The illustrated lock and the key structure has many advantages overconventional pin tumbler locks in that the key bit pins and the pintumbler permutations may be easily changed and especially in theprovision of the severable means for engaging the key and lock in theirhome positions for controlling the limits of relative rotation betweenthe plug and case when the key operates said plug.

While I have shown a particular embodiment of my invention, it will, ofcourse, be understood that I do not wish to be limited thereto, sincevarious modifications may be made in the key and lock constructionswithout departing from the spirit and scope of my invention as set forthin the appended claims, and I contemplate by the appended claims tocover any such modifications as fall within the true spirit and scope ofmy invention.

What is claimed is:

1. In a tumbler lock, a hollow cylindrical case having a large forwardbore and a co-axially positioned small bore in the rear part andcommunicating with said forward bore, a forwardly facing shoulder withinthe case between the bores and disposed at right angles to the commonaxis of the bores, a plug having an enlarged forward end rotatable inthe large forward bore and having a forward face flush with the forwardface of the case, said plug having a small rear portion rotatable in therear bore, means on the plug engaging the rear end of the case forprecluding axial movement of the plug through the forward part of thecase, a row of angularly spaced apart holes formed in the plug andhaving restricted mouths communicating with the forward face of theplug, the case having a row of angularly spaced apart holes normally inalignment with corresponding holes in the plug, said aligned holes ofthe case passing through the forwardly facing shoulder and disposedparallel to the axis of the plug, a pair of pin tumblers in each of saidaligned holes in said plug and case, the forward end of each pair oftumblers being adapted to normally seat in the restricted mouth in theplug, spring means in each hole of the case urging a pair of tumblersforwardly, and bayonet slots formed on the forward portion of the case,said slots having an entrance portion parallel to the axis of the caseand a circular portion disposed at right angles to the entrance portionand concentric with the said axis of the plug.

2. In combination a tumbler lock having a hollow cylindrical caseprovided with a forward bore and a coaxially positioned small boreformed in the rear part of the case and communicating with the forwardbore, a plurality of pin tumblers arranged parallel with the axis of thecase, a plug having an enlarged forward end rotatable in the largeforward part of the bore and having a forward face flush with theforward face of the case, means on the plug engaging the rear end of thecase for precluding axial movement of the plug through the forward partof the case, the forward part of the case having bayonet slots formedtherein and including an entrance portion parallel to the axis of theplug and case and a circular portion at right angles to the entranceportion, a key having bit pins adapted to operate the pin tumblers, saidkey having an annular skirt surrounding the bit pins and adapted toencircle the cylindrical forward end of the case, and inwardly directedlugs formed on the skirt for engaging the entrance portions of the slotsin the case when the key is moved to its home position on the lock caseand moving in the circular portions of the bayonet slots to control therotary movement of the plug in the case.

3. In combination a tumbler lock having a hollow cylindrical case, anannular key engaging portion formed on the forward end of the case, aplug rotatable in the case, pin tumblers movable in the case and in theplug parallel to the common axis of said case and plug, an exterior,circular slot formed laterally in the key engaging forward end of thecase, a longitudinal entrance slot formed in said case end to establishcommunication between the forward face of the case and the circularslot, a key having bit pins adapted to operate the pin tumblers, saidkey having an annular flange surrounding the bit pins and adapted toencircle the annular key engaging portion of the case, and an inwardlyprojecting lug mounted on the flange for engagement in the entrance slotwhen the key is moved to its home position on the lock and moving in thecircular slot to control relative rotation of the key and the lock case.

References Cited in the file of this patent UNITED STATES PATENTS240,397 Ehmer Apr. 19, 1881 1,494,765 Barrett May 20, 1924 1,718,130Frischmuth June 18, 1929 1,984,202 Shinn Dec. 11, 1934 2,588,230 GeorgeMar. 4, 1952

